This is a longitudinal study of the relationship between degenerative changes in specific regions of the brain and clinical symptoms in Huntington's disease using volumetric brain imaging. It is possible to follow changes in specific brain regions over time using serial scans and to correlate these with clinical features of this devastating fatal neurodegenerative disorder. Findings so far are that both motor and cognitive changes are most strongly correlated with loss of volume in the caudate and putamen within the basal ganglia. These changes appear highly selective as at least in the early stage, there is no detectable change in the frontal cerebral cortex, an area also implicated in HD. It will be important to continue to follow a sufficiently large number of patients, to make valid correlations between brain regions and clinical symptoms. These studies are of great importance for planning treatment trials and also for clearly understanding the natural history of the disorder as a reference for the development of animal models, such as transgenic mouse models which are also under development in our same research program.